Selector



C. E. LOMAX April 26, 1960 SELECTOR 2 Sheets-Sheet l Filed Dec. 20. 1956NVENTOR,

CLARENCE E. LOMAX ATTY.

C. E. LOMAX April 26, 1960 SELECTOR 2 Sheets-Sheet 2 Filed DeC. 20. 1956wss? .E5

INVENTOR.

CLARENCE E. LOMAX ATTY.

United States Patent O SELECTOR Application December 20, 1956, SerialNo. 629,580 16 Claims. (Cl. 179-18) This invention relates to animproved control circuit for a step-by-step switch in general and, inparticular, to an improvement in a vertical to rotary change-overcontrol circuit of a step-by-step switch.

In the usual step-by-step switch of the two motion type, la line relaythereof is energized upon seizure of the switch and is thenintermittently operated by a series of incoming impulses, correspondingto a digit, to step the switch in its primary direction to select adesired group of outlets corresponding to the number of impulsesreceived. Means is then provided to promptly switch in another circuitto cause the switch to automatically select an idle outlet in theelected group.

In such switches a change-over relay of the slow acting type is usuallyused to switch in the circuit which causes the switch to automaticallyselect an idle outlet after the primary movement has been completed.

Such a change-over relay is energized when the line relay starts itsintermittent operation and is held operated during such operation andupon the completion of the intermittent operation is released aspromptly as possible thereby completing the circuit for causing theautomatic selection of the idle outlet.

As the number of received impulses will vary with the digit dialled andtherefore the group elected, the slow acting relay must be heldenergized for different periods of time and still be promptly releasedat the end ofany series of impulses to promptly start the automaticselection so that adequate time is given for the selection of theidleoutlet before another series of impulses is receivedwhich is to be sentover the selected outlet to another switch.

The usual slow acting relays are liable to release more slowly afterhaving received a greater number of impulses than after having receivedonly a few and thereforethere is the possibility of such a relay notalways acting as promptly as desired and thus not giving suicienttimefor the automatic selection of an idle outlet before the next seriesof impulses is received.

In order to overcome this ditliculty and standardize the time, afterreceipt of the series of impulses, when the change-over relay operates,I have provided an improved change-over relay which Will operatepromptly and always within the same time period, independent of thenumber of impulses received by the line relay. This relay is adoublewound, differentially connected, slow-to-operate relay.

The purpose of this invention is to produce an improvement in thechange-over of a step-by-step switch from primary to secondary motion bythe use of a doublewound, dilerentially connected, slow-to-operate relayas the change-over control relay. I have illustrated the invention inconnection with the well known step-by-step switch having vertical androtary motion.

It is an object of this invention to provide a step-bystep switch thatcan change its motion from one direction to another in a constant periodof time regardless ofthe number of steps taken in the rst direction.

It is another object of this invention to'provide a two motion switchwhich employs a doublewound, differentially connected control relaywhich causes the switch to change from its first to its second directionof motion.

It is still another object of this invention to provide a selector whichcan switch from vertical to rotary motion a fixed time after thevertical motion has been completed regardless of the number of verticalsteps taken, thereby enabling the selector to perform the change-over ina shorter period of time.

It is another object of this invention to provide a selector whichemploys a doublewound, diiferentially connected relay as its vertical torotary motion control, thereby enabling said selector to be changed fromrotary to vertical motion in the same period of time regardless of thenumber of vertical steps taken, thus enabling the selector to `engage anidle trunk in a shorter period o f time than pres ent selectors.

This relay will get two pulses for each dial pulse. The pulses aredelivered at alternate times and to two diiferent windings on thechange-over relay. The windings are such that the field created by eachwinding is in an opposite direction to that created by the other.Therefore the windings are so arranged that they attempt to cancel eachother. `This is the means employed for preventing magnetism frombuilding up in the relay with each dial pulse.

Figure l is one embodiment of the invention and discloses the use of adoublewound, differentially connected slow-to-operate relay to cause abattery searching selector to change over from vertical to rotarymotion. The relay in this embodiment has the vertical magnet connectedin yseries with one of its windings. Figure 2 is another embodiment ofthe invention and discloses another method of using a doublewound,difierentially connected relay to cause a selector to change fromvertical to rotary motion. In this embodiment the relay windings areenergized through the contacts of the vertical magnet. However, onlythose components necessary ,todescribe this claimed embodiment areincluded as the other components necessary to complete the entireselector can be of the standard type which could readily be added by oneskilled in the art.

Figure 3 is yet another embodiment of the invention and it alsodiscloses only those components necessary to describe this claimedembodiment for the same reason.

In this embodiment the doublewound, dilerentially connected relay has aresistor inserted in series with one of its windings during a certainportion of the time when that winding is energized.

Figure l is a iive relay battery-searching selector switch containing apulsing relay 1A, a holding relay 1B, a change over relay 1D, a switchthrough relay 1F, a stepping relay 1S, a rotary magnet lRM, a verticalmagnet IVM, and a release magnet. l

When the switch is seized, relay 1A is energized and dial tone providedin a well known manner. Relay 1A upon operating closes an obviouscircuit to ground for relay 1B at contacts 1A1. Relay 1B encrgizes: toprepare a circuit for the vertical magnet 1VM through the upper windingof relay 1D, at contacts 1B2 to complete a circuit from ground to thelower winding of relay 1S through resistor 1K1 at contacts 1B4, and toplace ground on lead C through contacts 1B1 to mark the selector busy toall preceding switches. Relay 1S does not operate at this time becausethe field created by the lower winding is not strong enough to operatethe relay. This is a method of pre-energizing relay 1S to make itoperate quickly when the upper winding is energized.

If the calling party hangs up before dialing, relay 1A restores, butrelay 1B being a slow-torelease relay remains closed for a period oftime. During that period of time a pulse is sent to the vertical magnet1VM which operates, from ground, through contacts 1F7, contacts vIAZ,contacts IDI, contacts 1B2, through the upper winding of relay ID, andthrough the vertical magnet 1VM to battery. `Relay ID is not operatedthrough its upper winding but a magnetic field is builtup. The verticalmagnet IVM is operated and steps the wiper of the switch one step in thevertical direction thereby causing the vertical-ol-normal contacts IVMZand 1VM3 to be closed and the vertical-oi-normal contacts IVMI to beopened. Relay 1B thereafter restores, and at contacts IBZopens thevertical magnet circuit, and at contacts IBS closes the circuit to therelease magnet. The release magnet is then operated `over an obviouspath and then restores the selector in -a well known manner. Y

When the calling party starts dialing, relay 1A is restored by each dialpulse. When relay IA is restored by the rst dial pulse it closes acircuit to the vertical magnet IVM as has been described. The verticalmagnet 1VM operates and opens its spring contacts IVMI, and steps thewiper of the switch one step in the vertical direction thereby closingthe vertical-oi-normal springs IVM2 and IVMS and opening thevertical-offnormal springs IVMI. During the time that the verticalmagnet IVM is operated, a current is owing through the upper Winding ofrelay ID but the eld created thereby is not sufficient to operate therelay. Relay l1B being a slow-to-release relay, remains operatedthroughout the pulsing of relay 1A.

Relay IA reoperates after the rst pulse and opens the circuit to thevertical magnet IVM and the upper winding of relay ID at break contactsIAZ, thereby causing the vertical magnet IVM to restore. 'Ihe verticalmagnet upon restoring closes a circuit to the lower winding of relay 1D,from ground at contacts IB4,

"through break contacts IVMI of the vertical magnet,

contacts IVMS of the vertical-off-norrnal springs, through the lowerwinding of relay ID to battery.

The current through the lower winding of relay 1D is in the oppositedirection to the current through the upper winding. The vertical magnetIVM is not restored long enough between pulses to operate relay 1D. Thesecond pulse, which occurs when relay 1A restores again, operates thevertical magnet IVMI which opens its armature springs I, thereby openingthe circuit to the lower winding of relay ID. -As has been pointed outwhen the vertical armature operates, current ows through the upperwinding of relay ID. This current creates a iield which is opposite tothat created by the lower winding. The purpose of the upper winding isto act as a cancellation winding for the lower winding so that the lowerwinding will not build up magnetism in relay ID due to the repeatedpulses.

It should be pointed out at this time that the current starts flowingthrough the upper winding while current is still flowing through thelower winding since some time is required for the vertical magnet tooperate after its energization circuit has been closed. Therefore theoperating power for relay ID, that is, the field created by the currentthrough the lower winding is reduced before the vertical armature moves,thus aiding the upper winding to more quickly dispose of the eld of thelower winding.

When relay 1A comes to rest in the operated position at the end of thedialled digit, the current through the lower winding of relay ID createsa eld which is energized long enough to operate the relay 1D.

As relay ID operates it opens another point in the circuit for its upperwinding, the vertical magnet 1VM, and the release magnet, at contactsIDI. At contacts 1D2, it closes a holding circuit for itself fromground, through make contacts YIBi, through contacts IDZ, through thelower Winding of relay 1D to battery. At contacts 1D4, it prepares acircuit for relay 1S. At contacts ID3, it closes a circuit to the rotarymagnet IRM from ground, contacts ID3, contacts ISZ, contacts IFS, therotary cam springs 1, the rotary magnet interrupter contacts IRMI, andthe rotary magnet IRM to battery. The rotary magnet energizes androtates the shaft and its wipers to the rst set of bank contacts, and ifno battery potential is encountered by wiper C', rotates the wipers tothe next set of bank contacts and so on until an idle switch is found.The' rotary magnet opens its own circuit at contacts IRMI and therebyautomatically rotates the shaft and wipers until an idle switch isfound.

As soon as battery potential appears on lead 1C, indicating an idleswitch, relay 1S is operated from ground, contacts 1D4, the upperwinding of relay 1S to battery on lead IC.

Relay 1S when operated opens the circuit to the rotary armature at breakcontacts 1S2, and closes a cir cuit to relay IF, from ground, throughthe contacts ID3, and ISI to the winding of relay 1F and battery.

Relay 1F, upon operating, extends the calling line conductors, -L and--L, at contacts 1F2 and 1F4, respectively, and completes a holdingcircuit for itself from ground on the C lead at springs IBI extended,through contacts IF6 to battery. The seized switch which upon beingseized also places a ground on the wiper extended over the contacts IFSand 1F6 to provide holding ground for relay 1F upon the release of therelay 1B.

Upon opening of the contacts IFI and IFS, the relay IA releases andopens the circuit to relay 1B at contacts 1A. Relay 1B restores andopens the circuit to relay 1D at conatcts 1B4 thereby releasing relay1D, and prepares a circuit to the release magnet through the contact ID3which does not operate until the relay 1F releases and closes itscontacts IF7.

Relay 1D upon releasing, opens the circuit for relay 1S at contacts ID4.Relay IS then drops out leaving the switch through relay IF as the onlyrelay operated. Relay 1F is released when the holding ground removedfrom lead wiper C. To close an obvious circuit to the release magnet atcontacts 1F7 thereby causing the switch to be returned to normal in awell known manner.

Various arrangements of the change-over relay and the vertical magnetcan easily be made without departing from the scope of this invention.

Figure 2 shows an arrangement comprising a modiiied form of theinvention whereby the change-over relay 2D is energized through thesprings of the vertical magnet. Both the vertical magnet and thechange-over relay are in separate circuits. Only those componentsnecessary to describe this embodiment of the invention are shown and theremainder of components necessary to complete the entire selector can beof the standard type which can be readily added by one skilled in theart. s

Figure 2 contains a pulsing relay 2A, intermittently operated by aseries of impulses such as those caused by the operation of a dial,holding relay 2B, which is a slowto-release relay, relay 2D, whichcauses the change-over from vertical to rotary motion after thecompletion of the series of impulses to the pulsing relay, a verticalmagnet ZVM, a rotary magnet 2RM, and a release magnet.

When the calling subscriber initiates the call the pulsing relay 2A isenergized in a well known manner, and completes an operating circuit torelay 2B from ground, extending through contacts ZAI, and the winding ofrelay 2B to battery. Relay 2B upon operating prepares a circuit to thevertical magnet ZVM by closing the contact ZBI.

When relay 2A restores in response to the tirst pulse, relay 2B being aslow-to-release relay stays operated during the restoration of relay 2Aand a circuit extending to the vertical magnet is closed, from ground,through contacts 2A2, 2B1, 2D1rotary cam springs 21 tobattery.

The vertical magnet operates and steps the switch one step in thevertical direction thereby closing the verticaloff-normal springs 2VM3.

vmake contacts 2VM1, to

The vertical! magnet then closes its spring contacts 2VM1 therebycompleting 'a circuit to the upper winding of relay 2D, from ground,through the vertical-off-normal springs 2VM3, armature battery. K d

The current flowing through the upper winding of relay 2D is notsufficient to create a field capable of operating the relay.

Relay 2A then re-operates after the first pulse and opens the circuit tothe vertical magnet ZVM at its contacts ZVMZ. The vertical magnet thenrestores and opens the circuit to the upper winding offrelay 2D atcontacts 2VM1, and closes a circuit to the lower winding of relay 2D atcontacts '2VM2, from ground, through the verticaloff-normal contacts2VM3 and 2VM2 through the lower winding of relay D, to battery. Thuscurrent is caused to flow in the lower winding of relay 2D. The fieldproduced in the lower winding of relay 2D is opposite to field in theupper winding.

The Vertical magnet ZVM is not restored long enough between pulses tooperate relay 2D. Thel second pulse which occurs when Vrelay 2A restoresresponsive to the series of impulses operates the vertical magnet ZVM ashas been explained, thereby closing its contacts 2VM1 to again energizethe upper winding of relay 2D, and opens the circuit to the lowerwinding of relay 2D at contact 2VM2. The field created by this upperwinding of relay 2D is Aopposite toy that created by the lower windingof relay 2D and tends to cancel the lfield remaining in the lowerwinding. The purpose of the upper winding is to act as a cancellationwinding for the lower winding so that the lower' winding will not buildup magnetism in the relay due to the repeated pulsing.

After the end of the dialed digit the current through the lower windingis not interrupted and, after the counter effect of its upper windingceases, relay 2D energizes, Yand upon operation closes a circuit for therotary magnet 2RM, from ground, extending'throu'gh the contacts ZDZ andthe interruptor contacts 2-RM2 and rotary 4magnet to battery. Theremainder of the operation can be conventional 'and is not pertinent tothis embodiment of the invention. p

Still another embodiment of the invention is shown in Figure 3. Figure`3 like Figure 2 is not a complete drawing of afstep-by-step switch suchas Figure 1 wherein the invention is shown as applied to a selector. Oneskilled `in the a'rt would have no difficulty in adding the necessarycomponents to complete the entire selector since the omitted componentscan be of the standard type.

Figure 3 contains a pulsing relay 3A, a holding relay 3B, a change-'overrelay 3D, a vertical magnet SVM, and a rotary magnet SRM. p n

When a calling subscriber initiates a call, the pulsing relay 3A isseized in awell known manner. When relay 3A operates it closes a`circuit to the holding relayl 3B from ground, through contacts BA1 andwinding of relay 3B to battery. d

Relay 3B is a slow-to-release relay and stays operated during theintermittent operation of relay 3A which is operated responsive to thedial pulsing of a dialed digit. Relay 3B upon venergizing prepares acircuit to the changeover relay 3D and the vertical magnet 3VMatcontacts BB3.

When relay 3A lrestores responsive to the 'rst dial pulse it closes acircuit towboth the vertical magnet SVM and the upper winding of thechange-over relay 3D, from ground through the contacts 3 A2 of relay 3A,contacts 3B3, contacts 3D4, contacts SVMS and the upper winding of relay3D t'o battery and through the vertical magnet SVM to battery. The upperwinding of the change-over relay could operate the relay'except thatresistor R1 is placed in series with the 'upper winding near the end of-the armature stroke when contacts SVMS open. The current is also cutdown to the vertical magnetby the insertion of the resistorSRlbut themomen-y relay 3D is again closed as Yturn of the shaftitself operated bythevertical'magnet wouldfcause the'shaft to finish its stroke. Y 1

The vertical magnet SVM causes the switch totstepv off normal and closea circuit to the lower, or operating winding of relay 3D from ground, tothe vertical-'olfnorrnal contacts 3VM7 and 3VM6, and through the lowerwinding of relay 3D to battery. However, contacts 3VM6 of the verticalmagnet are so arranged that they open at the beginning of the stroke andthe circuit therefore has no effect on the operation of relay 3D at thistime. p

When relay 3A reoperates during its intermittent operation it opens thecircuit to the vertical magnet BVM and upper winding of relay 3D. Thevertical magnet restores and closes a circuit to the lower winding ofrelay 3D which is the operate winding, from ground, 3VM7 and BVM6,through the lower winding of relay 3D to battery. The current throughthe lower winding of relay 3D does not have time to operate the relayduring pulsing of relay 3A. The magnetic field created by the lowerwinding is opposite to the magnetic field created by the upper winding.The circuit to the upper winding of has been described.y The purpose ofthe upper winding of relay 3D is to act as a cancellation winding forthe lower winding which is the operate winding to prevent magnetism frombuilding up in the relay due to the pulsing. K

In this embodiment of the invention the initial surge to thecancellation winding is relatively larger than in the other embodimentsdiscussed and would not only cancelthe'operate field still remaining butwould operate the relay itself. However, a resistor SR1 is inserted linseries with the upper winding near the end of the vertical stroke of thevertical magnet and the field of the upper winding is thereby decreased.

The purpose of theresistor is to enable a strong field to be created inthe first winding of relay 3D without operating relay 3D.k The pulsingrelay 3A is intermittently operated responsive to a received number ofimpulses thereby. There is no assurance that every rseries of impulseswill have pulse lengths of equal length. The worst condition in 'as faras this design is concerned is when the pulse length is short to thepulsing relay thereby causing the pulsing relayto be released a smaller'percentage of the time than it is operated during the intel'- mittentoperation.

This shorter release time of the pulsing relay will cause the secondwinding of relay 3D to be energized a longer period of time andtherefore require a stronger field in the first winding of relay 3D toeliminate the buildfup of magnetism in the relay.

Therefore in order to create as strong a field as practical in the firstwinding of relay 3D without operating relay 3D a resistor has beeninserted to reduce the field of the lfirst winding before the firstwinding can operate the relay.

It can now be seen that the alternate pulsing of Vthe two windings ofthe change-over relay 3D during the dialing of the digit by the callingparty eliminates magnetism from being built up in the relay and enablesthe relay to be so wound that a considerable amount of time can be savedin transferring the vertical motion of a step-by-step switch to rotarymotion.

What has been described are considered to be the preferred embodimentsof the invention and -it is to be further understood that othermodifications both in structure and manner of operation may be madewithout departing from the scope of my invention as defined in thevclaims which follow.

What is claimed is:

l. In a selector switch having pulse responsive means for stepping awiper in a vertical and rotary motion, a vertical to rotary motionchange-over control relay, a first and a` second winding on said relay,first circuit means operable during the vertical stepping of said wiperor energizing :indue-energizing said first windi'rigof -said firstwinding of said relay,

stepping, thereby enabling said relay to operate at a constant period oftime after the vertical stepping of .said wiper has been` completedregardless of the number -of vertical steps said switch wiper has'taken.

2. -A step-by-step'selector switch as claimed in claim l wherein saidfirstcircuit means and said second circuit means, operable duringthevertical stepping of said wiper for energizing and de-energizing saidfirst winding and vsaid second winding of said relay, energizeandde-energize said first winding and said second winding once for eachvertical step of said wiper.

3. In a step-by-step switch as claimed in claim 1 wherein said rstcircuit means, operable during the vertical stepping of said wiper forenergizing and de-energizing comprises a pulsing relay, aslow-to-release holding relay, and a vertical magnet connected in serieswith .the first winding of said control relay, said pulsing relaycausing the operation of said holding relay upon initial operation ofsaid pulsing relay, subsequently said pulsing relay being intermittentlyoperated responsive to a series of impulses received thereby, saidholding relay remaining operated during said intermittent operation ofsaid pulsing relay thereby enabling said pulsing relay to cause saidfirst winding of said control relay and said vertical magnet to beenergized and de-energized, each energization of said vertical magnetcausing said wiper to be stepped one step.

4. A step-by-step switch as claimed in claim 1 wherein said secondcircuit means, operable during the vertical stepping of said wiper forenergizing and de-energizing said second winding of said control relay,comprises a pulsing relay, a slow-to-release holding relay, and a vertical magnet connected in series with said first winding of said controlrelay, said pulsing relay causing the operation of said holding relayupon initial operation of said pulsing relay, subsequently said pulsingrelay being intermittently operated responsive to a series of impulsesreceived thereby, said holding relay remaining operated during saidintermittent operation of said pulsing relay thereby enabling saidpulsing relayy to cause said first winding of saidcontrol relay and saidvertical magnet to be intermittently energized, each energization ofsaid vertical magnet causing said wiper to be stepped one step, eachdeenergization of said vertical magnet causing said second winding ofsaid control relay to be energized.

5. A selector switch having a pulse responsive means for stepping awiper in a vertical and rotary motion comprising a pulsing relay havinga set of make and break contacts operated thereby, a slow-to-releaseholding relay having a set of make contacts operated thereby, an operatepath for said holding relay completed by said make contacts of saidpulsing relay in response to the operation of said pulsing relay, avertical to rotary motion changeover control relay having a first andsecond winding, a vertical magnet connected in series with said firstwinding, said magnet having a set of break contacts operated thereby, anenergization path for said first winding and said vertical magnetcompleted through said break contacts of said pulsing relay and saidmake contacts of said holding relay responsive-to the release of saidpulsing relay and the operation of said holding relay, an energizationpath for said second Winding completed through said break contacts ofsaid vertical magnet upon release of said vertical magnet, said pulsingrelay upon initial 'operation causing said holding relay to be operated,said pulsing relay subsequently being intermittently operated responsiveto a series of impulses received thereby and remaining operatedthereafter, said holding relay remaining operated during said series ofimpulses to said pulsing relay, said energization path for Ysaid firstwinding and said vertical magnet and said energization path of saidsecond winding alternately closed responsive to each release andoperation of said pulsing relay, said energization path for said firstwinding and said vertical magnet being completed when said pulsing relayis released, through said break contacts of said pulsing relay and saidmake contacts of said holding relay, said vertical magnet causing saidwiper to be stepped one step responsive to each successive energizationof said vertical magnet, said energization path for said second windingbeing completed when said vertical magnet is released through said breakcontacts of said vertical magnet, said first and said second windingupon being energized producing magnetic fields which oppose each otherand thereby eliminate any build-up of magnetism in said control relay assaid pulsing relay is intermittently operated, said energization pathfor said second winding remaining completed after said intermittentoperation of said pulsing relay to thereby operate said control relay,said operation of said control relay causing said wiper to change fromvertical to rotary motion, said elimination of said magnetic build-up insaid control relay and said completion of said second winding after saidintermittent operation, enabling said wiper to change from vertical torotary motion a fixed period of time after the last impulse has beenreceived by said pulsing relay regardless of the number of impulses insaid series of impulses.

6. A selector switch having pulse responsive means for stepping a wiperin a vertical and rotary motion comprising, a pulsing relay, aslow-to-release holding relay, a vertical to rotary motion change-overcontrol relay having a first and a second winding, and a verticalmagnet, said pulsing relay upon initial operation causing said holdingrelay to be operated, said holding relay thereafter preparing a circuitto said vertical magnet, said pulsing relay subsequently beingintermittently operated in response to a series of impulses receivedthereby and remaining operated thereafter, said holding relay remainingoperated during said impulsing, said pulsing relay causing said verticalmagnet to be intermittently operated responsive to the intermittentoperation of said pulsing relay thereby causing said wiper to bevstepped in the vertical direction, said vertical magnet upon operationduring said intermittent operation causing said first winding to beenergized and upon release of said vertical magnet causing said secondwinding to be energized, both windings producing magnetic fields whichoppose each other thereby preventing the build-up of magnetism in saidcontrol relay during said stepping of said switch, said vertical magnetafter vertical stepping has been completed causing said second windingto remain energized to thereby operate said control relay to cause saidswitch to change from vertical to rotary stepping, said elimination ofsaid build-up of magnetism in said relay and said cornpletion of saidsecond winding after said intermittent operation, enabling said wiper tochange from vertical to rotary motion a fixed time after said lastimpulse is received by said pulsing relay regardless of the number ofimpulses in said series.

7. In a selector switch having wipers and a magnet for moving saidwipers in a primary movement and means for moving said wipers in asecondary movement, a pulsing relay energizesd when said switch isYseized, said pulsing relay thereafter intermittently operated inresponse to received impulses to operate the wipers in their primarymovement, a change-over relay having a first and a second winding, meanscontrolled by the intermittent operation .0f Said pulsing relay for..intermittently closing y9 a circuit for said magnet and said firstwinding to thereby intermittently operate said magnet to move saidswitch in said primary movement and intermittently energize said firstwinding, and means controlled by the intermittent operation of saidmagnet for intermittently closing a circuit for said second windingduring receipt of said impulses and for maintaining said circuit forsaid second winding closed thereafter, the fields created in saidchange-over relay during said intermittent energization of said windingsopposing each other to prevent any build up of magnetism in saidchange-over relay during said intermittent energization, said continuedenergization of said second winding afterpthe completion of saidintermittent pulsing and said elimination of any build up of magnetismin said change-over relay thereby enabling said relay to operate apredetermined period of time after the cessation of said impulses tothereby cause the operation of said means for moving the wipers in saidsecondary movement a fixed period of time after the completion of saidimpulses to said pulsing relay.

8. In a switch having a movable wiper means responsive to the recepit ofimpulses for selectively stepping said wiper in a primary or secondarymovement, means for transferring said stepping means from primary tosecondary motion, comprising: a differentially connected relay having a1st and 2d winding first; circuit means for creating a field in saidfirst winding; second circuit means for creating an opposing field insaid second winding, said first and second circuit means each actuatedonce for each step of said switch in the primary movement; meansresponsive to cessation of said received pulses for rendering said firstcircuit means ineffective and enabling said relay to operate a fixedtime following said cessation; and means controlled by the operation ofsaid relay for transferring said stepping means from the primarymovement to the secondary movement.

9. In a two-motion switch; having a wiper means operated responsive tothe receipt of impulses for stepping the wiper; a differentiallyconnected relay having two windings; circuit means for energizing eachof said windings once for each step of said wiper; means for causingsaid relay to operate a predetermined time after cessation of saidpulses to said stepping means; and means controlled by the operation ofsaid relay for enabling further operation of said switch.

10. In a two-motion switch having a movable wiper; means responsive tothe receipt of impulses for selectively stepping said wiper in a primaryor secondary movement; a differentially connected relay having a pair ofwindings, said windings being so constructed as to produce opposingfields when energized; circuit means for energizing each of saidwindings once for each step of said switch in the primary movement;means responsive to cessation of said received pulses for controllingsaid circuits means and enabling said relay to operate at a fixed timethereafter; and means controlled by the operation of said relay fortransferring said stepping means from the primary movement to thesecondary movement.

11. In a two-motion switch having a movable wiper; means responsive tothe receipt of impulses for sequentially stepping said wiper in avertical and rotary movement; a relay having two windings each of saidwindings being constructed as to produce a field which, when energized,opposes the field produced by the other winding; circuits means forenergizing each of said windings once for each step of said wiper in thevertical direction; means responsive to cessation of pulses tosaidswitch for controlling said circuit means and enabling said relay tooperate; and means controlled by the operation of said relay fortransferring said stepping means from the vertical movement to a rotarymovement, whereby the windings of said relay are energized to producethe vertical portion of the wiper movement and energizing current to onewinding is discontinued upon cessation of the pulses to enable saidrelay to operate at a fixed time -after such cessation.

1`2. In a two-motion switch having a movable wiper means operatedresponsive to the receipt of impulses for stepping said wiper invertical or rotary movement; a relay having a pair of windings; circuitmeans for alternately energizing each of said windings once for eachstep of said switch in the verticaly direction, each of said windingsoperable upon energization to cancel the effect of any residualmagnetism in the other winding; means responsive to cessation of saidpulses for controlling said circuit means to discontinue energization ofone of said windings to 'enable said relay to operate a `fixed timethereafter; and means controlled by the operation of said relay fortransferring said stepping means from a primary movement to a secondarymovement, whereby said relay is prevented from operation by the build-upof residual magnetism therein and is operated a fixed time after thecessation of pulses to the stepping switch without regard to the numberof pulses received by said switch.

13. In a twomotion switch having a movable wiper; means responsive tothe receipt of impulses for selectively stepping said wiper in a primaryor a secondary direction; a relay having a pair of windings each windingbeing so constructed that the field produced therein, when energized,opposes the field of the other winding; circuit means for energizingeach of said windings once for each step of said wiper in said primarydirection; means responsive to cessation of pulses to said steppingmeans to control said circuit means and enable said relay to operate afixed time after cessation; and means controlled by the operation ofsaid relay for transferring said stepping means from the primarymovement to the secondary movement, whereby the opposed windings of saidrelay prevent operation thereof prior to cessation of the pulses to saidstepping means and prevent build-up of residual magnetism so that saidrelay operates a fixed time thereafter.

14. In a selector switch having pulse responsive means for stepping awiper in a vertical and rotary motion, means independent of the numberof pulses in a series, operable a fixed time after cessation thereof fortransferring the wiper stepping means from vertical to rotary motion,comprising; a vertical to rotary motion changeover control relay havinga first and second winding; a vertical magnet connected in series withthe first winding of said control relay operable to step said wiper in avertical direction one step for each operation thereof; a pulsing relayincluded in said pulse response adapted to receive pulses and beintermittently operated thereby; a slow-to-release holding relayoperated and held operated by the operation of said pulsing relay; afirst operating circuit for energizing said first winding to create amagn netic field therein and said vertical magnet, said circuitincluding a normally open contact on said holding relay and a normallyclosed contact on said pulsing relay for energizing said vertical relayand said first winding for each intermittent operation of said pulsingrelay; a second circuit actuated under control of said pulsing relay toenergize said second winding to create a magnetic field therein which isopposed to the magnetic field in said first Winding to prevent operationof said control relay by the build-up of a magnetic field in said firstwinding, whereby said second winding is unopposedly energized only uponcessation of pulses to said pulsing relay.

15. A selector switch having a pulse responsive means for stepping awiper in a vertical and rotary motion, comprising: a pulsing relay,included in said pulse responsive means, having a set of make and breakcontacts operated thereby; a slow to release holding relay having a setof make contacts operated thereby; a vertical magnet intermittentlyenergized by operation of said pulsing relay to step said wiper in avertical direction once for each pulse received thereby, said magnethaving a set of make and a set of break contacts operated thereby;

, 11 an operating circuit'including the rnaln'contactsY on said pulsingrelay for intermittently supplying energizing current toV said holdingrelay to 4operate' said relay and hold it operated throughout theoperation of said pulse responsive means; a vertical magnetoperatingcircuit conditioned through the make contact on said holdingrelay and operated through the break contact on said pulsing relay; anda vertical to rotary motionl changeover control relay having a rstWinding energized through the closure of the make contact on saidvertical magnet, and a second winding energized through the breakcontact on said vertical magnet, said first and second winding eachcreating a eld opposed to the other upon energization `to neutralize themagnetic elds created therein, whereby said relay is held againstoperations by said tirst winding during the receipt of impulses and isoperated by said second winding upon cessation of the pulses.

16. The switch of claim 13 wherein the circuit means for transferringthe stepping means from Yprimary to secondary motioncornprises; anoperating circuit including make contacts operated by said pulsing relayto supply energizing current to said holding relay during'receipt ofimpulses; a parallel circuit including a vertical magnet and theA rstwinding of control relay; a resistor circuit on said diterentiallyconnected relay connected in series with said parallel circuit, saidcircuit including a resistor and anormally opened contact adapted to beclosed'by a'predetermined amount of operation of said vertical magnet,whereby the time of maximum energization of said first winding iscontrolled to prevent build up of suiiicient eld therein to cancel themaximum field in said second winding.

References Cited in the le of this patent UNITED STATES PATENTS2,529,402 Lomax Nov. 7, 1950 2,529,409 Newstedt Nov. 7, 1950 2,575,842Rudeforth Nov. 20, 1951 2,663,763 Lomaxv Dec. 22, 1953 2,731,515 WicksJan. 17, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OFrC()RR1ELCTIO1\I Ratent No. 2,934,607 April 26, 1960 Clarence E. LomaxIt is hereby certified that error appears in the-printed specificationof the above -numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

I Column 9, line 73, after "produce" insert opposing fields to preventoperation of the relay during Signed and sealed this 31st day of January1961.

(SEAL) Attest: KARL f1. AXLINE i ROBERT c. WATSON y"'Attesting OfficerCommissioner of Patents Ratent No. 2,934,607

UNITED STATES PATENT OFFICE CERTIFICATE 0E coRREcTToN April :26l 1960Clarence E. Lomax pears in theprinted specificationl It is herebrcertified that error ap rrection and that the said Letters of the abovenumbered patent requiring co Patent should read as corrected below.

Column 9, line 73, after "produce" insert opposing fields to preventoperation of the relay during Signed and sealed this 31st day of Januaryl96l (SEAL) Attest:

IARL n AXLNE I ROBERT c. WATSON Attesting Ofcer Commissioner of Patents

